I call it brain freeze with good reason. In one of my previous lives, I was working as a flag woman at construction zones on various roadways.
When I'd get home after 8 or more hours of standing in the same spot directing traffic in blasted cold weather, I literally suffered from brain freeze. Never mind that I couldn't untie my work boots or unzip my coat by myself, I couldn't even think clearly enough to put one foot in front of the other to make my way across the room.
The only thing that saved me was my partner helping me crawl into a tub of warm water and as I slowly started to thaw out, she would add a little more hot water until my color started coming back and I could actually start thinking for myself again.
Makes me really appreciative of having an inside job when it's winter. but of course, being human, I bitch about being stuck inside in summer. Shish!